Composition for forming electrode of solar cell, and electrode manufactured using same

ABSTRACT

A composition for solar cell electrodes and electrodes fabricated using the same. The composition includes a silver (Ag) powder; a glass frit containing about 0.1 mole % to about 50 mole % of elemental silver; and an organic vehicle, wherein the elemental silver derives from a silver halide (Ag—X). The composition introduces a glass frit including a silver halide to enhance contact efficiency between electrodes and a silicon wafer, and solar cell electrodes prepared from the composition have minimized contact resistance (Rc), specific contact resistivity, and serial resistance (Rs), thereby exhibiting excellent conversion efficiency.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. national phase application of PCT Application No.PCT/KR2013/011534, filed Dec. 12, 2013, which is based on Korean PatentApplication No. 10-2012-0157695, filed on Dec. 29, 2012, and KoreanPatent Application No. 10-2013-0152676, filed on Dec. 9, 2013, theentire contents of all of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a composition for solar cell electrodesand electrodes fabricated using the same.

BACKGROUND ART

Solar cells generate electricity using the photovoltaic effect of a p-njunction which converts photons of sunlight into electricity. In thesolar cell, front and rear electrodes are formed on upper and lowersurfaces of a semiconductor wafer or substrate with the p-n junctions,respectively. Then, the photovoltaic effect at the p-n junction isinduced by sunlight entering the semiconductor wafer and electronsgenerated by the photovoltaic effect at the p-n junction provideelectric current to the outside through the electrodes. The electrodesof the solar cell are formed on the wafer by applying, patterning, andbaking an electrode composition.

Continuous reduction in emitter thickness to improve solar cellefficiency may cause shunting which may deteriorate solar cellperformance. In addition, solar cells have been gradually increased inarea to achieve higher efficiency. In this case, however, there may be aproblem of efficiency deterioration due to increase in solar cellcontact resistance.

Therefore, there is a need for a composition for solar cell electrodesthat may enhance contact efficiency between electrodes and the siliconwafer to minimize contact resistance (Rc) and serial resistance (Rs),thereby providing excellent conversion efficiency.

DISCLOSURE Technical Problem

It is one object of the present invention is to provide a compositionfor solar cell electrodes which exhibits excellent contact efficiencybetween an electrode and a surface of a wafer.

It is another object of the present invention is to provide acomposition for solar cell electrodes capable of minimizing contactresistance, specific contact resistivity and serial resistance.

It is a further object of the present invention is to provide acomposition for solar cell electrodes having excellent conversionefficiency and fill factor.

It is further object of the present invention is to provide solar cellelectrodes prepared from the composition.

The above and other objects can be achieved by the present inventiondescribed in detail in the following.

Technical Solution Advantageous Effects

In accordance with one aspect of the invention, a composition for solarcell electrodes includes a silver (Ag) powder; a glass frit containingabout 0.1 mole % to about 50 mole % of elemental silver; and an organicvehicle, wherein the elemental silver may derive from a silver halide(Ag—X).

The composition may include about 60% by weight (wt %) to about 95 wt %of the silver powder; about 0.1 wt % to about 20 wt % of the glass frit;and about 1 wt % to about 30 wt % of the organic vehicle.

The glass frit may contain about 0.5 mole % to about 25 mole % ofelemental silver based on a total mole number of the glass frit.

The glass frit may be formed of at least one metal oxide and a silverhalide (Ag—X).

The metal oxide may include at least one metal oxide selected from thegroup consisting of lead (Pb), bismuth (Bi), tellurium (Te), phosphorus(P), germanium (Ge), gallium (Ga), cerium (Ce), iron (Fe), lithium (Li),silicon (Si), zinc (Zn), tungsten (W), magnesium (Mg), cesium (Cs),strontium (Sr), molybdenum (Mo), titanium (Ti), tin (Sn), indium (In),vanadium (V), barium (Ba), nickel (Ni), copper (Cu), sodium (Na),potassium (K), arsenic (As), cobalt (Co), zirconium (Zr), manganese(Mn), and aluminum (Al) oxides.

In the silver halide (Ag—X), X may be an elemental halogen selected fromamong iodine (I), fluorine (F), chlorine (Cl), and bromine (Br).

The glass frit may have an average particle diameter (D50) of about 0.1μm to about 10 μm.

The composition may further include at least one additive selected fromthe group consisting of dispersants, thixotropic agents, plasticizers,viscosity stabilizers, anti-foaming agents, pigments, UV stabilizers,antioxidants, and coupling agents.

In accordance with another aspect of the invention, a solar cellelectrode formed of the composition for solar cell electrodes isprovided.

Advantageous Effects

A composition for preparing solar cell electrodes according to thepresent invention introduces a glass frit including silver halide toenhance contact efficiency between an electrode and a wafer, and solarcell electrodes prepared from the composition have minimized contactresistance (Rc), specific contact resistivity and serial resistance(Rs), thereby exhibiting excellent fill factor and conversionefficiency.

DESCRIPTION OF DRAWINGS

FIG. 1 is a scanning electron microscope (SEM) of a solar cell electrodeprepared using a glass frit in accordance with one embodiment of thepresent invention.

FIG. 2 is a schematic view of a solar cell in accordance with oneembodiment of the present invention.

BEST MODE

Composition for Solar Cell Electrodes

A composition for solar cell electrodes according to the presentinvention includes a silver (Ag) powder (A); a glass frit containingelemental silver (B); and an organic vehicle (C).

Now, each component of the composition for solar cell electrodesaccording to the present invention will be described in more detail.

(A) Silver Powder

The composition for solar cell electrodes according to the inventionincludes silver (Ag) powder as a conductive powder. The particle size ofthe silver powder may be on nanometer or micrometer scale. For example,the silver powder may have a particle size of dozens to several hundrednanometers, or several to dozens of micrometers. Alternatively, thesilver powder may be a mixture of two or more types of silver powdershaving different particle sizes.

The silver powder may have a spherical, flake or amorphous shape.

The silver powder preferably has an average particle diameter (D50) ofabout 0.1 μm to about 10 μm, more preferably about 0.5 μm to about 5 μm.The average particle diameter may be measured using, for example, aModel 1064D (CILAS Co., Ltd.) after dispersing the conductive powder inisopropyl alcohol (IPA) at 25° C. for 3 minutes via ultrasonication.Within this range of average particle diameter, the composition mayprovide low contact resistance and low line resistance.

The silver powder may be present in an amount of about 60 wt % to about95 wt % based on the total weight of the composition. Within this range,the conductive powder may prevent deterioration in conversion efficiencydue to increase in resistance and difficulty in forming the paste due torelative reduction in amount of the organic vehicle. Advantageously, theconductive powder may be present in an amount of about 70 wt % to about90 wt %.

(B) Glass Frit Containing Elemental Silver

The glass frit serves to enhance adhesion between the conductive powderand the wafer or the substrate and to form silver crystal grains in anemitter region by etching an anti-reflection layer and melting thesilver powder so as to reduce contact resistance during the bakingprocess of the composition for electrodes. Further, during the bakingprocess, the glass frit softens and lowers the baking temperature.

When the area of the solar cell is increased in order to improve solarcell efficiency, there may be a problem of increase in solar cellcontact resistance. Thus, it is necessary to minimize both serialresistance (Rs) and influence on the p-n junction. In addition, as thebaking temperatures varies within a broad range with increasing use ofvarious wafers having different sheet resistances, it is desirable thatthe glass frit secure sufficient thermal stability to withstand a widerange of baking temperatures.

In one embodiment, the glass frit is formed from a silver halide (Ag—X)and a metal oxide. Specifically, the glass frit may be prepared bymixing, melting, and pulverizing a silver halide having a melting pointof 600° C. or less, which is lower than the melting point of elementalsilver; and a metal oxide. The metal oxide may include at least one kindof metal oxide.

In the silver halide (Ag—X), X may include iodine, fluorine, chlorine,or bromine. Preferably, X is iodine.

The metal oxide may include at least one metal oxide selected from thegroup consisting of lead (Pb), bismuth (Bi), tellurium (Te), phosphorus(P), germanium (Ge), gallium (Ga), cerium (Ce), iron (Fe), lithium (Li),silicon (Si), zinc (Zn), tungsten (W), magnesium (Mg), cesium (Cs),strontium (Sr), molybdenum (Mo), titanium (Ti), tin (Sn), indium (In),vanadium (V), barium (Ba), nickel (Ni), copper (Cu), sodium (Na),potassium (K), arsenic (As), cobalt (Co), zirconium (Zr), manganese(Mn), and aluminum (Al) oxides.

The glass frit may contain about 0.1 mole % to about 50 mole % ofelemental silver, preferably about 0.5 mole % to about 25 mole % ofelemental silver based on the total mole number of the glass frit.

The content of elemental silver may be measured by an inductivelycoupled plasma-optical emission spectrometry (ICP-OES). ICP-OES requiresa very small sample amount, and thus may shorten sample set-up time andreduce errors due to pre-treatment of the sample while providingexcellent analytical sensitivity.

Specifically, ICP-OES may include pre-treating a sample, preparing astandard solution, and calculating the content of elemental silver in aglass frit by measuring and converting the concentration of elementalsilver (Ag), thereby enabling accurate measurement of the content ofelemental silver in the glass frit.

In operation of pre-treating a sample, a predetermined amount of thesample may be dissolved in an acid solution capable of dissolving ananalysis target, that is, silver (Ag) in a sample glass frit, and thenheated for carbonization. The acid solution may include a sulfuric acid(H₂SO₄) solution.

The carbonized sample may be diluted with a solvent, such as distilledwater or hydrogen peroxide (H₂O₂), to an appropriate extent that allowsanalysis of elemental silver. In view of element detection capability ofan inductively coupled plasma-optical emission spectrometer (ICP-OES),the carbonized sample may be diluted 10,000 times.

In measurement with the ICP-OES, the pre-treated sample may becalibrated using a standard solution, for example, an elemental silverstandard solution (Ag+ 1000 mg/L) for measuring elements.

By way of example, calculation of the content of elemental silver in theglass frit may be accomplished by introducing the standard solution intothe ICP-OES and plotting a calibration curve with an external standardmethod, followed by measuring and converting the concentration (ppm) ofelemental silver in the pre-treated sample using the ICP-OES.

Solar cell electrodes manufactured from the glass frit according to thepresent invention may have Ag crystals precipitated on the glass frit inaddition to Ag crystals formed from the conductive powder after baking.Moreover, elemental silver deriving from silver cyanide or silvernitrate may impart conductivity to glass that is formed between the Agcrystals and a wafer on the glass frit and acts as an insulator betweenthe Ag crystals and the wafer, and may fill isolated pores or voids onthe glass frit, thereby reducing contact resistance and serialresistance of the wafer-silver electrodes.

FIG. 1 is a scanning electron microscope (SEM) of a solar cell electrodeprepared using a glass frit in accordance with the present invention,and spherical particles are Ag crystals precipitated in the glass shownin FIG. 1 (a). The Ag crystals may be distributed uniformly within theglass, thereby enhancing conductivity between the silver electrodes andthe wafer.

The glass frit may be prepared from such metal oxides by any typicalmethod known in the art. For example, the metal oxides may be mixed in apredetermined ratio. Mixing may be carried out using a ball mill or aplanetary mill. The mixture is melted at 700° C. to 1300° C., followedby quenching to 25° C. The obtained resultant is subjected topulverization using a disk mill, a planetary mill, or the like, therebypreparing a glass frit.

The glass frit may have an average particle diameter (D50) of about 0.1μm to about 10 μm, and may have a spherical or amorphous shape.

The glass frit may be present in an amount of about 0.1 wt % to about 20wt %, preferably about 0.5 wt % to about 10 wt %, based on the totalweight of the composition. Within this range, it is possible to securep-n junction stability given varying surface resistances whileminimizing serial resistance so as to improve solar cell efficiency.

(C) Organic Vehicle

The organic vehicle imparts suitable viscosity and rheologicalcharacteristics for printing to the composition for solar cellelectrodes through mechanical mixing with the inorganic component of thecomposition.

The organic vehicle may be any typical organic vehicle used in solarcell electrode composition, and may include a binder resin, a solvent,and the like.

The binder resin may be selected from acrylate resins or celluloseresins. Ethyl cellulose is generally used as the binder resin. Inaddition, the binder resin may be selected from among ethyl hydroxyethylcellulose, nitrocellulose, blends of ethyl cellulose and phenol resins,alkyd, phenol, acrylate ester, xylene, polybutane, polyester, urea,melamine, vinyl acetate resins, wood rosin, polymethacrylates ofalcohols, and the like.

The solvent may be selected from the group consisting of, for example,hexane, toluene, ethyl cellosolve, cyclohexanone, butyl cellosolve,butyl carbitol (diethylene glycol monobutyl ether), dibutyl carbitol(diethylene glycol dibutyl ether), butyl carbitol acetate (diethyleneglycol monobutyl ether acetate), propylene glycol monomethyl ether,hexylene glycol, terpineol, methylethylketone, benzylalcohol,γ-butyrolactone, ethyl lactate, and combinations thereof.

The organic vehicle may be present in an amount of about 1 wt % to about30 wt % based on the total weight of the composition. Within this range,the organic vehicle may provide sufficient adhesive strength andexcellent printability to the composition.

(D) Additives

The composition may further include typical additives to enhance flowand process properties and stability, as needed. The additives mayinclude dispersants, thixotropic agents, plasticizers, viscositystabilizers, anti-foaming agents, pigments, UV stabilizers,antioxidants, coupling agents, and the like, without being limitedthereto. These additives may be used alone or as mixtures thereof. Theseadditives may be present in the composition in an amount of about 0.1 wt% to about 5 wt %, without being limited thereto.

Solar Cell Electrode and Solar Cell Including the Same

Other aspects of the invention relate to an electrode formed of thecomposition for solar cell electrodes and a solar cell including thesame. FIG. 2 shows a solar cell in accordance with one embodiment of theinvention.

Referring to FIG. 2, a rear electrode 210 and a front electrode 230 maybe formed by printing and baking the composition on a wafer or substrate100 that includes a p-layer (or n-layer) 101 and an n-layer (or p-layer)102, which will serve as an emitter. For example, a preliminary processof preparing the rear electrode 210 is performed by printing thecomposition on the rear surface of the wafer 100 and drying the printedcomposition at 200° C. to 400° C. for 10 seconds to 90 seconds. Further,a preliminary process for preparing the front electrode may be performedby printing the paste on the front surface of the wafer and drying theprinted composition. Then, the front electrode and the rear electrodemay be formed by baking the wafer at 600° C. to 1000° C., preferably at750° C. to 950° C., for 30 seconds to 180 seconds.

Next, the present invention will be described in more detail withreference to examples. However, it should be noted that these examplesare provided for illustration only and should not be construed in anyway as limiting the invention.

MODE FOR INVENTION Examples

Preparation of Glass Frit:

Glass frits of Examples and Comparative Examples were prepared accordingto the compositions as listed in Table 1. The prepared glass frits wereevaluated as to the content (unit: mole %) of elemental silver thereinusing an Inductively Coupled Plasma-Optical Emission Spectrometer(ICP-OES). Representative results of which are shown in Table 3.

Example 1

As an organic binder, 3.0 wt % of ethylcellulose (STD4, Dow ChemicalCompany) was sufficiently dissolved in 6.5 wt % of butyl carbitol at 60°C., and 87.1 wt % of spherical silver powder (AG-4-8, Dowa Hightech Co.,Ltd.) having an average particle diameter of 2.0 μm, 2.9 wt % of a glassfrit prepared according to the composition as listed in Table 1, 0.2 wt% of a dispersant BYK102 (BYK-Chemie), and 0.3 wt % of a thixotropicagent Thixatrol ST (Elementis Co., Ltd.) were added to the bindersolution, followed by mixing and kneading in a 3-roll kneader, therebypreparing a composition for solar cell electrodes.

Examples 2 to 32 and Comparative Examples 1 to 2

Compositions for solar cell electrodes were prepared in the same manneras in Example 1 except that the glass frits were prepared according tothe compositions as listed in Table 1 and 2.

TABLE 1 (unit: wt %) AgI PbO Bi₂O₃ TeO₂ P₂O₅ Li₂CO₃ SiO₂ ZnO WO₃ MgOCeO₂ SrCO₃ MoO₃ TiO₂ SnO In₂O₃ Example 1 2 — 39 50 — 2 7 — — — — — — — —— Example 2 5 — 40 50 — 2 3 — — — — — — — — — Example 3 10 — 35 50 — 2 3— — — — — — — — — Example 4 20 — 30 40 — 2 8 — — — — — — — — — Example 540 — — 50 — 2 8 — — — — — — — — — Example 6 2 40 — 50 — 2 6 — — — — — —— — — Example 7 5 40 — 50 — 2 3 — — — — — — — — — Example 8 10 35 — 50 —2 3 — — — — — — — — — Example 9 20 30 — 40 — 2 8 — — — — — — — — —Example 10 30 25 — 35 — 2 8 — — — — — — — — — Example 11 2 38 — 50 2 2 —6 — — — — — — — — Example 12 5 27 — 50 7 2 — 9 — — — — — — — — Example13 10 29 — 50 5 2 — 4 — — — — — — — — Example 14 20 29 — 40 3 2 — 6 — —— — — — — — Example 15 30 25 — 43 2 — — — — — — — — — — Example 16 2 —39 50 — 2 5 2 — — — — — — — — Example 17 5 — 40 50 — 2 2 — 1 — — — — — ——

TABLE 2 (unit: wt %) AgI PbO Bi₂O₃ TeO₂ P₂O₅ Li₂CO₃ SiO₂ ZnO WO₃ MgOCeO₂ SrCO₃ MoO₃ TiO₂ SnO In₂O₃ Example 18 10 — 35 50 — 2 2 — — 1 — — — —— — Example 19 20 — 30 40 — 2 5 — — — — — 3 — — — Example 20 30 — 25 35— 2 5 — — — — — — — 3 — Example 21 2 39 20 32 — 2 5 — — — — — — — — —Example 22 5 40 40 11 — 2 2 — — — — — — — — — Example 23 10 35 35 16 — 22 — — — — — — — — — Example 24 20 30 30 13 — 2 5 — — — — — — — — —Example 25 30 25 25 13 — 2 5 — — — — — — — — — Example 26 2 40 20 21 — 5— 12 — — — — — — — — Example 27 5 40 40 8 — 2 — 5 — — — — — — — —Example 28 10 35 35 9 — 2 — 9 — — — — — — — — Example 29 20 30 30 10 — 5— 5 — — — — — — — — Example 30 30 25 25 6 — 3 — 11 — — — — — — — —Example 31 18 — 30 40 — 2 8 — — — — — — — — 2 Example 32 18 — 30 40 — 28 — — — — — — 2 — — Comparative — — 40 50 — 2 7 1 — — — — — — — —Example 1 Comparative — 25 — 60 — 2 8 5 — — — — — — — — Example 2

Measurement of Content of Elemental Silver in Glass Frit Using ICP-OES

Pretreatment of Samples:

0.5 g of a glass frit sample to be analyzed was placed in a beaker andcorrectly weighed to within ±0.0001 g. 200 ml of 5 mole % sulfuric acid(H₂SO₄) was added to the beaker, followed by heating at 220° C. for 3hours using a hot plate, thereby completely carbonizing the sample.Hydrogen peroxide (H₂O₂) was added to the beaker until the beakercontaining the carbonized sample became transparent, thereby completingthe pretreatment.

Preparation of Standard Solution:

An elemental silver standard solution (Ag+ 1000 mg/L) for measuringelements was prepared.

Measurement of the Content of Elemental Silver:

Nitric acid was added to the beaker containing the pre-treated sample,followed by heating for 5 minutes and air cooling. The prepared standardwas introduced into an ICP-OES tester and a calibration curve wasplotted by an external standard method, followed by measuring andconverting the concentration (ppm) of elemental silver in the sampleusing the ICP-OES tester (PerkinElmer, Inc.), thereby calculating theconcentration of elemental silver in the glass frit.Content of elemental silver (%)=Concentration of element (ppm)×DilutionFactor (DF)/10000Mole of elemental silver=Content of elemental silver/Molecular weight ofelemental silverMole % of elemental silver=Mole of elemental silver/total mole number ofall elements

TABLE 3 Content of elemental silver (mole %) Example 1 1.09 Example 22.88 Example 3 5.12 Example 4 10.44 Example 5 19.16 Comparative 0Example 1 Example 26 0.82 Example 27 2.74 Example 28 5.52 Example 2911.19 Example 30 16.95 Comparative 0 Example 2

Measurement Method of Contact Resistance and Specific ContactResistivity

The compositions prepared in the examples and comparative example weredeposited onto a front surface of a crystalline mono-wafer by screenprinting in a predetermined pattern, followed by drying in an IR dryingfurnace. Cells formed according to this procedure were subjected tobaking at 600° C. to 900° C. for 30 seconds to 210 seconds in abelt-type baking furnace, and then evaluated as to contact resistance(Rs) and specific contact resistivity (ρc) using a TLM (Transfer LengthMethod) tester. The measured contact resistance and specific contactresistivity are shown in Table 4 and 5.

Measurement Method of Serial Resistance, Fill Factor, and ConversionEfficiency

The compositions prepared in the examples and comparative examples weredeposited over a front surface of a crystalline mono-wafer by screenprinting in a predetermined pattern, followed by drying in an IR dryingfurnace. Then, the aluminum paste was printed on a rear side of thewafer and dried in the same manner as above. Cells formed according tothis procedure were subjected to baking at 400° C. to 900° C. for 30seconds to 180 seconds in a belt-type baking furnace, and evaluated asto serial resistance (Rs), Fill Factor (FF, %), and conversionefficiency (%) using a solar cell efficiency tester CT-801 (Pasan Co.,Ltd.). The measured serial resistance, fill factor, and conversionefficiency are shown in Table 4 and 5.

TABLE 4 Specific contact Contact Resistance resistivity SerialResistance (Rc) (mΩ) (mΩ · cm²) (Rs) (mΩ) Fill Factor Efficiency (%)Example 1 0.5701 0.9530 5.10 76.57 16.81 Example 2 0.5144 0.8547 5.0576.68 16.91 Example 3 0.4689 0.6838 4.86 76.82 17.01 Example 4 0.41830.5622 4.79 76.89 17.14 Example 5 0.3173 0.4567 4.38 77.14 17.42 Example6 0.6187 1.0313 5.06 76.65 16.88 Example 7 0.5173 0.8585 4.97 76.7416.93 Example 8 0.4717 0.6898 4.83 76.84 17.08 Example 9 0.4472 0.63154.75 76.96 17.21 Example 10 0.3706 0.4795 3.90 77.26 17.46 Example 110.6545 1.1656 6.02 75.80 16.24 Example 12 0.5669 0.9028 5.41 76.16 16.43Example 13 0.5103 0.8402 5.32 76.34 16.61 Example 14 0.4669 0.6619 5.1876.48 16.76 Example 15 0.4221 0.5871 4.92 76.80 17.00 Example 16 0.49560.8000 5.34 76.27 16.58 Example 17 0.4284 0.6242 5.20 76.47 16.75

TABLE 5 Specific contact Contact Resistance resistivity SerialResistance (Rc) (mΩ) (mΩ · cm²) (Rs) (mΩ) Fill Factor Efficiency (%)Example 18 0.4028 0.5578 4.86 76.82 17.04 Example 19 0.3982 0.5200 4.7876.93 17.16 Example 20 0.3860 0.4832 4.50 77.14 17.39 Example 21 0.61871.0313 5.47 76.09 16.33 Example 22 0.5505 0.8997 5.25 76.39 16.67Example 23 0.5058 0.8189 5.14 76.53 16.78 Example 24 0.4928 0.7021 5.0176.73 16.92 Example 25 0.3982 0.5200 4.81 76.86 17.09 Example 26 0.63181.0436 5.35 76.22 16.55 Example 27 0.5415 0.8974 5.22 76.45 16.72Example 28 0.5082 0.8261 5.07 76.59 16.85 Example 29 0.4935 0.7633 4.8576.83 17.04 Example 30 0.4621 0.6552 4.76 76.93 17.19 Example 31 0.44810.6325 4.71 76.99 17.22 Example 32 0.4522 0.6399 4.63 77.11 17.28Comparative 1.0325 1.7413 7.35 73.75 15.30 Example 1 Comparative 1.25451.9797 9.02 72.50 14.94 Example 2

As shown in Table 4 and 5, it could be seen that the solar cellelectrodes fabricated using the compositions prepared using the glassfrit that contains elemental silver deriving from a silver halide inExamples 1 to 32 had considerably low contact resistance, specificcontact resistivity, and serial resistance, thereby providing excellentfill factor and conversion efficiency, as compared with those ofComparative Example 1 to 2.

It should be understood that various modifications, changes,alterations, and equivalent embodiments can be made by those skilled inthe art without departing from the spirit and scope of the invention.

The invention claimed is:
 1. A composition for solar cell electrodes,comprising: a silver (Ag) powder; a glass fit containing about 0.1 mole% to about 50 mole % of elemental silver; and an organic vehicle,wherein the elemental silver derives from a silver halide (Ag—X).
 2. Thecomposition according to claim 1, comprising: about 60 wt % to about 95wt % of the silver powder; about 0.1 wt % to about 20 wt % of the glassfit; and about 1 wt % to about 30 wt % of the organic vehicle.
 3. Thecomposition according to claim 1, wherein the glass fit contains about0.5 mole % to about 25 mole % of elemental silver.
 4. The compositionaccording to claim 1, wherein the glass fit is formed from at least onemetal oxide and a silver halide (Ag—X).
 5. The composition according toclaim 4, wherein the metal oxide includes one or more of lead oxide,bismuth oxide, tellurium oxide, phosphorus oxide, germanium oxide,gallium oxide, cerium oxide, iron oxide, lithium oxide, silicon oxide,oxide zinc, tungsten oxide, magnesium oxide, cesium oxide, strontiumoxide, molybdenum oxide, titanium oxide, tin oxide, indium oxide,vanadium oxide, barium oxide, nickel oxide, copper oxide, sodium oxide,potassium oxide, arsenic oxide, cobalt oxide, zirconium oxide, manganeseoxide, or aluminum oxide.
 6. The composition according to claim 1,wherein, in the silver halide (Ag—X), X is iodine (I), fluorine (F),chlorine (Cl), or bromine (Br).
 7. The composition according to claim 1,wherein the glass frit has an average particle diameter (D50) of about0.1 μm to about 10 μm.
 8. The composition according to claim 1, furthercomprising: one or more of a dispersant, a thixotropic agent, aplasticizer, a viscosity stabilizer, an anti-foaming agent, a pigment, aUV stabilizer, an antioxidant, or a coupling agent.
 9. A solar cellelectrode prepared from the composition for solar cell electrodesaccording to claim 1.